What you know might surprise you.
The advice to drink eight glasses of water a day is repeated so often it feels like medical law. But the origin of that number is surprisingly shaky — and your body may already be doing a better job of managing hydration than any fixed rule ever could.
If you grew up in America, someone almost certainly made you wait 30 minutes after lunch before getting back in the pool. It was enforced like a rule of nature. The actual science behind it is a lot less convincing than your parents' tone of voice suggested.
The warning has been passed down through generations: crack your knuckles and you'll pay for it with arthritis later. One California doctor was so unconvinced that he ran a decades-long experiment on himself to find out. The results might make you feel a lot better about that satisfying pop.
Before Reddit became the front page of the internet, there was Digg — a scrappy, user-powered news aggregator that dominated the mid-2000s web and then spectacularly imploded. Here's the wild story of how it happened, why it matters, and what Digg is up to today.